(1) Field of the Invention
The invention relates to a burglarproof device for a locking fitting, comprising at least a locking organ, such as a hook bolt or the like, capable of protruding with respect to the front edge of said leaf, so as to co-operate with a keeper inserted against the corresponding stile of the sash-frame.
This invention will find its application in the field of building ironmongery and in particular relates to fittings for a sliding leaf.
(2) Description of the Prior Art
As a matter of fact, there are already known various locking fittings meeting the above-description. In particular, there is known a locking fitting for a sliding leaf of a door, window or the like comprising at least an operating rod installed in a groove or a notch present in the fillister of the front stile of this sliding leaf. As a matter of fact, this operating rod moves at the rear of a faceplate, under the action of an adequate control mechanism, this in order to bring one or several locking organs, such as a hook bolt or the like, into an unlocked or, reversely, a locked position. In this latter case, this locking organ co-operates with a keeper inserted against the corresponding stile of the sash-frame.
The problem that such locking fittings present resides in the accessibility to the locking organ or organs or also to the keeper through the fillister of the door or window. Thus, it can not seldom be observed that in the event of burglary the opening of such a door or window has been controlled through a direct action exerted on this or these locking organs. Furthermore, one has been able to notice that a failed attempt of burglary carried out in such a way in most cases results into the malfunctioning of the locking fitting. A locking fitting, such as a hook bolt, made directly integral with an operating rod and protruding from the faceplate through an opening in this latter indeed remains relatively fragile per se, depending on the kind of stress directly imparted to this hook bolt. In addition, very often the keepers have, at their inner and/or outer side faces, an "undercut" shape allowing the insertion of a tool, such as a screwdriver or the like, which also results in seriously damaging this keeper, in particular its securing to the sash-frame.
Furthermore, in particular from EP-0,262,067, it is known a locking fitting for a sliding-type door or window the leaf and the sash-frame of which are designed through an assembly of tubular profile bars made of synthetic material or aluminum, such profile bars defining, at the level of the front edge of said sliding leaf and also at the level of the corresponding stile of the sash-frame, U-shaped grooves. Through such a configuration, this front stile of the leaf is capable of fitting on the corresponding stile of the sash-frame while covering said U-shaped groove of this latter.
Finally, it seems that through such a particular configuration of the profile bars the sliding door or window is comprised of and in which are accommodated the hook bolt and the keeper of the locking fitting, such profile bars, whether they are made of aluminum or, all the more so, of synthetic material, are, in fact, in no way capable of somehow withstanding the aggression with a tool, such as a screwdriver or the like, that a burglar may use during an attempt of burglary.